Whilst we're on the subject of spooks, by the way, this tale on Slugger O'Toole is completely ridiculous, for reasons fully explained in a comment I left there.
Simply, the Government has plenty of places to go underground right huurr in the South-East, without needing to go to Northern Ireland (seriously! the only part of the British Isles where you can be certain there really are terrorists!). The RAF and various other agencies still use large chunks of the Corsham bunker under Box Hill, and there are also the various bunkers along the A40 - PJHQ/CINCFLEET at Northwood, and RAF Strike Command at High Wycombe.
I really have to stop this Dsquared-esque habit of posting comments that really ought to be posts on either TYR or AFOE.